Field of the Invention
Embodiments of the present invention generally relate to an apparatus for thermally processing a substrate. In particular, embodiments of the present invention relate to simplified, high voltage, tungsten halogen lamps for use as a source of heat radiation in a rapid thermal processing (RTP) chamber or other lamp heated thermal processing chambers.
Description of the Related Art
During RTP of substrates, thermal radiation is generally used to rapidly heat a substrate in a controlled environment to a maximum temperature of up to about 1350° C. This maximum temperature is maintained for a specific amount of time ranging from less than one second to several minutes depending on the particular process. The substrate is then cooled to room temperature for further processing.
High voltage, e.g., about 40 volts to about 130 volts, tungsten halogen lamps are commonly used as the source of heat radiation in RTP chambers. High voltage tungsten halogen lamps require a fuse in the circuit to prevent arcing and potential explosion in the lamp during lamp failure. Providing the fuse internal to the capsule of the lamp is difficult to implement due to small capsule size and potential contamination affecting the halogen cycle. Providing the fuse in the press seal of the lamp may result in undesirable cracking or breaking of the press seal. Thus, it is desirable to incorporate the fuse external to the capsule and press seal. Current lamp designs include a number of additional components (e.g., stainless steel tube, ceramic potting compound, plugs) in order to provide a fuse external to the capsule and press seal while providing sufficient rigidity to the leads for mating to a heating assembly base of an RTP chamber.
Therefore, it is desirable to provide a simplified, high voltage, tungsten halogen lamp design to reduce cost and provide arc protection during lamp failure.